Aircraft Stringers with CFRP-Reinforced Flanges for Impact and Buckling

The patent applies composite materials by combining CFRP (carbon fiber reinforced plastic) reinforcement segments with conventional composite stiffening segments. The CFRP flanges are integrated with the stiffening segments to create a hybrid composite structure that enhances impact strength and buckling resistance while maintaining the benefits of composite material construction throughout the stringer assembly.

The patent applies parameter changes by optimizing the ply drop ratio to specific ranges (chordwise: 3-30, spanwise: 120-300). These controlled parameter specifications for ply termination stagger distances prevent thermal cracking and wrinkle formation during curing and operation, while the staggered ply drop design maintains manufacturing feasibility through defined geometric constraints.

The patent applies segmentation by dividing the stringer into distinct functional segments: CFRP reinforcement segments for the flanges and conventional composite stiffening segments for the web and other areas. This segmented approach allows targeted reinforcement where buckling strength is critical (at the flanges) while maintaining simpler construction in other regions, optimizing the strength-to-complexity ratio.

The patent applies parameter changes by establishing specific ratio ranges for ply drop configuration (chordwise ratio: 3-30, spanwise ratio: 120-300). These parameter specifications control the stagger distances between ply terminations to prevent delamination and maintain structural integrity, while allowing manufacturing flexibility within the defined ratio boundaries rather than requiring exact fixed distances.